New Study Looks at When and Where Climate Change Could Cause Biodiversity Loss

April 2020 - We have long understood that climate change can drive species loss. Researchers have also done studies about when individual species could face dangerously high temperatures under different scenarios. But how might species loss play out in whole communities across the globe over the next century? Three researchers from universities on three continents recently got together to find out. Their study reveals that species loss in a given area is not likely to be gradual as temperatures steadily climb. Instead, it is likely to be sudden, and sometimes catastrophic.

The researchers based their study on the known ranges of more than 30,000 marine and terrestrial plants and animals. They used that range data, plus climate data from 1850-2005, to figure out each species’ known temperature tolerances. Then, they modeled when and where each of those known tolerances would be exceeded under standard greenhouse gas emissions scenarios. Under a “business as usual” scenario (representative concentration pathway (RCP) 8.5), their models indicate that sudden spikes in species losses could begin as soon as 2030 in tropical oceans. Similar spikes in tropical forests could follow as soon as 2050. Furthermore, they find that 15% of plant and animal communities could risk suddenly losing more than 20% of their species to extended periods of unprecedented high temperatures by 2100. If we reduce emissions to limit warming to 2 °C (RCP 2.6), less than 2% of communities would face similar risks. In other words, limiting emissions would make a huge difference in reducing the risk of catastrophic species losses in most communities.

Interactive maps of some the researchers’ findings are available for all to explore. For example, clicking on Pinnacles National Park reveals that under RCP 8.5, 14% of species in the area could face extended periods of hotter temperatures than any they are currently known to tolerate by 2100. Of those at-risk species, 46% could exceed their known temperature tolerances within the same decade, between 2062 and 2072. Under RCP 2.6, around 2% of species at Pinnacles might have their known temperature tolerances similarly exceeded by 2100. What are the species exposure rates and timelines for other San Francisco Bay Area national parks? Check out the maps to find out!

For more information

• Trisos, C.H., Merow, C. & Pigot, A.L. (2020) The projected timing of abrupt ecological disruption from climate change. Nature 580, 496–501.
• Corresponding author Alex Pigot's website
• Climate change could cause sudden biodiversity losses worldwide, University College London press release
• Wildlife Collapse From Climate Change Is Predicted to Hit Suddenly and Sooner, The New York Times

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